The objective of this proposal is to develop a series of standardized tests of alveolar macrophage function in normal man and to define abnormalities in various pulmonary disease states. The specific aims are: 1. To define the functional capabilities of the normal alveolar macrophage and to determine differences between smokers and nonsmokers. 2. To determine the structural and elemental content of alveolar macrophages in normal man and in certain disease states. 3. To develop a reliable cytotoxicity assay for human alveolar macrophages and define the macrophage's cytotoxic capacity against neoplastic cells with particular reference to lung cancer. 4. To determine alterations of human pulmonary macrophage function in certain disease states including lung cancer, chronic bronchitis, pneumoconiosis, asthma, cystic fibrosis, and others. 5. To determine the effect of kaolinite on human alveolar macrophage function. Pulmonary macrophages are recovered by bronchopulmonary lavage. The studies to be performed include cytochemistry, transmission electron microscopy, scanning electron microscopy, and proliferative capacity by 3H-thymidine incorporation and clonogenicity in semi-solid gel culture. Cell function studies include glass adherence, spreading, phagocytosis, fungicidal and bactericidal capacity, chemotaxis, and cytotoxicity. Elemental analysis will be performed by scanning microprobe and mass X-ray fluorescence spectrometry and ion-scattering spectrometry.